A 90th-minute goal from Kosta Barbarouses consigned Glory to a 3-2 defeat against Melbourne Victory at AAMI Park on Saturday.
The visitors had taken an early lead through Scott Neville before the hosts responded with efforts from James Troisi and Mark Milligan either side of the break.
Diego Castro's sumptuous lob seven minutes from time then looked to have secured Kenny Lowe's side a battling point, but Barbarouses had the final word by sliding home his sixth goal of the season right at the death.
On a rainy night in the Victorian capital, Glory produced an improved display having made the best possible start when 18-year-old Walter Scott marked his starting debut by delivering a superb cross which Scott Neville headed home with just 90 seconds on the clock.
Victory gradually worked their way into the game, however and levelled things up just before the half-hour mark when Castro conceded possession on halfway, George played a one-two with Besart Berisha and although Liam Reddy kept out the Dutchman's shot, Troisi was on hand to bundle home the loose ball.
Seemingly unaffected by the setback, Glory came agonisingly close to restoring their lead moments later when Jacob Italiano teed up Adam Taggart only for the Socceroos striker to be foiled by Matt Acton at close range.
Instead it was Kevin Muscat's men who hit the front almost immediately after the break as George's pinpoint free-kick was clipped home by Milligan.
Again Glory dug deep, however and duly made it 2-2 via a goal with a distinctly Spanish flavour.
Andreu showed great vision with the through-ball and Castro displayed wonderful skill and composure to lob Acton after the home 'keeper had ill-advisedly charged from his line.
At that stage, the men in purple looked poised to secure a valuable point, but Barbarouses had other ideas and following another fine pass from the impressive George, the New Zealand international found the bottom corner to seal the win and send the home fans into raptures.
Glory remain seventh ahead of Thursday's trip to Brisbane Roar.
Melbourne Victory 3 (Troisi 27', Milligan 47', Barbarouses 90' ) Perth Glory 2 (Neville 2', Castro 83')
Half time: 1-1
AAMI Park, Melbourne
Referee: Alex King
Assistant Referee 1: Anton Shchentinin
Assistant Referee 2: Daniel Ilievski
Fourth Official: Lachlan Keevers
Video Assistant Referee: Jarred Gillett
Melbourne Victory: 1.Matt ACTON (Gk), 2.Jason GERIA, 3.Dino DJULBIC (6.Leigh BROXHAM 72'), 5.Mark MILLIGAN, 8.Besart BERISHA, 9.Kosta BARBAROUSES, 10.James TROISI (31.Christian THEOHAROUS 80'), 21.Carl VALERI (c), 22.Stefan NIGRO, 24.Terry ANTONIS, 41.Leroy GEORGE (18.Matias SANCHEZ 90')
Substitutes not used: 23.Jai INGHAM, 40.Matthew SUTTON
Yellow cards: Antonis
Red cards: None
Perth Glory: 33.Liam REDDY (gk), 2.Alex GRANT (4.Shane LOWRY 79'), 8.Xavi TORRES, 9.Andy KEOGH (c), 17.Diego CASTRO, 18. Andreu GUERAO, 22.Adam TAGGART (6.Mitch NICHOLS 57'), 23.Scott NEVILLE, 26.Jacob ITALIANO (14.Chris HAROLD 79'), 29.Jeremy WALKER, 37.Walter SCOTT
Substitutes not used: 3.Marc WARREN, 13 Nick FEELY (Gk)
Yellow cards: Walker, Grant
Red cards: None